Orthogonal frequency division multiplexing (OFDM) is a form of multiplexing that distributes data over a number of carriers that have a very precise spacing in the frequency domain. The precise spacing of the carriers provides several benefits such as high spectral efficiency, resiliency to radio frequency interference and lower multipath distortion. Due to its beneficial properties and superior performance in multi-path fading wireless channels, OFDM has been identified as a useful technique in the area of high data-rate wireless communication, for example wireless metropolitan area networks (MANs). Wireless MANs are networks to be implemented over an air interface for fixed, portable, and mobile broadband access systems.
In wireless communications using OFDM, a transmission resource used by a base station for transmission to a mobile station may be assigned as a number of basic access units (BAUs).
In order to enable small enough granularity to support certain types of traffic, such as voice over internet protocol (VoIP), the size of BAUs needs to be relatively small. Typically the result is a large number of BAUs within in a slot and, correspondingly, a large amount of resource assignment overhead.
As resources consumed by signaling cannot be used for transmitting data, reducing resource assignment overhead would allow a larger amount of data to be transmitted on the resource.